Gathoni Mwaniki inside a greenhouse.

Beneficiary of Mastercard  and  KCB Foundations sponsored project, Gathoni Mwaniki  on a  mission  to popularize   hydroponic farming

By Joseph Macharia

Her consuming passion for hydroponics gained momentum after going to Israel for eleven  months as part of agricultural training. Having attended Jomo Kenyatta University Agriculture of Technology (JKUAT) where she had graduated summa cum laude with a bachelor in agricultural, business and management before leaving for Israel, Gathoni returned a transformed person with a renewed zeal. She was  determined to put into use the knowledge she had learnt. She felt challenged that a small country on a desert can thrive on  agriculture using hydroponics while back home,  agriculture was still practised traditionally.

Fortunately, fate smiled upon her in 2020 where she landed an opportunity to be one of the young farmers to be sponsored by Mastercard and KCB foundations to do hydroponic farming for a contract period of five years in Kibiko, Ngong. The two foundations built one hundred  green houses and supplied inputs. Each  greenhouse was assigned  two people to manage it. With this, she was set to explore the world of hydroponic farming as a practitioner. Presence of a ready local market and her previous exposure to  farming  of tomatoes  led her to choose tomato Anna F1 from a list that included coloured capsicum and cucumbers.

Sharp-witted, soft-toned and affable, Gathoni who has now turned into an agri-tour host says tomato hydroponic farming was the best thing that has ever happened to her. To her, farming is like art; an avenue for self-expression for living out a divine calling. “My farming journey has been rewarding. It gives me purpose. Tomato farming is one thing I’ll do even if I wasn’t getting paid,” she confesses with an unmistakable air of contentment. She even abandoned her part time job as an online writer to focus fully on training farmers about tomato farming using hydroponics.

The green houses are eight  by twenty four  metres translating to one hundred and ninety two  square  metres.  They  support  six hundred  plants spaced  forty  by  sixty  centimetres from each other. With each plant producing an average of ten  kg of tomatoes during the entire season, she has been harvesting six  tons ( six thousand kilogrammes ) every year. Notably, it can get to thirteen to fifteen kilogrammes  per plant,  netting seven to ten  tons. It takes  three  months for the plant to grow and the following  six  months to produce fruits. She harvests her fruits twice every week. All her tomatoes are bought by Lattia, a company that has been supplying agronomist expertise. Grade  one  and two, typically the large tomatoes are bought at around Kshs. 45  to 50 per kilogramme. Take out your calculator and face the numbers!

Welcome to ‘soil-less’ farming

Chances are, you haven’t any slightest idea of what hydroponics is. Well, you are not alone! Stripped to its essence, hydroponic farming is growing of crops without using soil. “How?” I can hear your little voice shouting skeptically. “It’s a fun fact, plants don’t need soil, but they need nutrients. So you can spray nutrients or in another type of hydroponics you can use water only without soil,” Gathoni explains noting that it has been in practice for a century. Some countries have successfully been practising  hydroponic farming   to improve their food security.

Back to science lessons, your teacher was on point when he taught (or can we say preached) that plants need three things :  water, air and warmth (light). The soil upon which the project is located was tested and it was  found that  it contained fulsarium wilt, a soil borne virus that  is very lethal. “Once your plant is infected with fulsarium wilt, the only solution is to uproot it. If you don’t, it spreads to the other plants. So hydroponics is one of the ways to avoid it altogether,” she elaborates. To practise hydroponics farming you need perfect water that is neutral since plants are very sensitive. Water from their borehole too was found to contain sodium. They have therefore  been using water from the county government company since it  is safe for human consumption.

Instead of soil which may contain soil-borne viruses, they were provided with pumis and cocopeats. Basically, these are substances without nutrients that will hold the roots of a plant. “We use a mixture of pumis and cocopeats. We mix it  in a way that a third of the mixture is composed of cocopeats.  The remaining two-thirds  is   pumis. Although you can use cocopeat in its entirety, it’s a little bit expensive and  that is   why we mix that way,” Gathoni explains adding that cocopeat is made from coconut husks. What is  interesting is that you can grow crops on the same pumis or cocopeats as many times as you wish.

Tomatoes planted in rows on a mixture of pumis and cocopeat.


Firstly,  hydroponic farming does not come with soil-borne diseases. With hydroponics,  you eliminate all the soil-borne diseases which increases the chances for a descent harvest,  while lowering the costs that would otherwise be spent on controlling the diseases. Additionally, cases of pests and diseases are lower because of the existence of the net as a first line of defense. Contrary to popular opinion, Gathoni asserts that the perfect way to practise organic farming is by  using a greenhouse. “If you want to  practise  organic farming, the best way would be to use a greenhouse because you won’t face most of the pests. Hydroponics is the future, it has a lot of potential,”  she avers.

Another key advantage about hydroponics farming   is that it can be practised  anywhere; in the desert, on rocks on mountain tops or even on a balcony. Notably, cocopeat is lighter and is often used in high rise buildings.  It is also  very clean unlike soil which can get muddy when watered.

Tomatoes planted in a greenhouse using hydroponics can stay for  twenty days without going bad. The reason for this is that  the conditions inside the greenhouse are controlled. Given that spaces are shrinking due to a surge in population, vertical hydroponic farming which helps to maximize on space and increase production can be deployed to increase food output.


While she has experienced phenomenal success, along the way,  Gathoni has come face to face with some  challenges.  “The biggest challenge is hdyroponics’ fertilizers. They are very expensive because you have to give nutrients every day,” she says. Nutrients have to be given in solution form and cost about Kshs. 200 daily; for nine months it totals to over Kshs. 54,000. In comparison, an  eight  by  twenty four  greenhouse without hydroponics may use less than Kshs. 20,000 in fertilisers.

The other challenge she has encountered is diseases. While hydroponics farming rules out soil borne diseases, plants remain  vulnerable to fungal infections like early and late blight, botritis (black mold), downey and powdery mildew. The infections affect leaves, stems and fruits. “For blight,  you can have one hundred  percent loss meaning you may even have nothing to harvest,” she warns. Pests like white flies, spider mites and tuta absoluta can cause damage to crops. To manage these challenges calls for expertise.

“People in the market don’t like greenhouse produce. They have a misconception that the fruits have too much chemicals thus not fit for human consumption,” Gathoni laments refuting the misconception. In fact she suggests that greenhouse produce can be very organic because once you control diseases and pests,  you won’t be required to apply excessive chemicals.

The road ahead

“Farming is profitable, but there is  a caveat, it’s not a get-rich-quick-scheme, you have to do it on certain scale of at least  five hundred  square  feet or  three  standard greenhouses to realize a profit,” she says hinting that it doesn’t require much time to manage a greenhouse. She considers farming a core activity that we should all embrace.

“I would advise a new farmer to first find a market. Secondly, engage experts or an agronomist who has gone through the journey and is familiar with diseases for the first and second year,” she counsels. Her future plans is to set up her own hydroponic farm to grow tomatoes.  She is also planning to  continue  training  more people on tomato production once she exits the programme. In the same vein, she is the chairlady Kibiko Agri-Preneurs Women Group – Ngong.  The  ambitious  group  is  exploring ways through which  its members  can pool their resources to achieve financial freedom.

A sample of pumis and cocopeat mixture.

A day in the life of Gathoni

Habitually,  Gathoni  wakes up early. She  gets to the greenhouse by 8.30 am.  By  then,  plants have already fed for the first time, which usually happens at 8.00 am.  She does maintenance tasks such as de-leafing, de-suckering, scouting for pests and feeding until noon, when the greenhouse becomes too hot to work in comfortably.  After that, she  takes a break, during which she checks on her social media platforms, mainly Facebook and LinkedIn, where she posts regularly under the name Gathoni Mwaniki. Most of  the days,  she leaves the greenhouse at between two  and three in the afternoon  depending on the amount of farm work that needs to be  done  ( though she outsources some of the work such as trellising to experts at the farm). She is a voracious reader and you will often find her listening to audiobooks as she goes about her business. Her favourite meal is ugali with  spinach or pigweed.   Gathoni  is not a picky eater and  she  has no allergies to food.



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